[Xen-devel] [PATCH 4/4] xen: Introduce a xmemdup_bytes() helper

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Use it to simplify the x86 microcode logic, taking the opportunity to drop the
-ENOMEM printks.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/cpu/microcode/amd.c   |  9 ++-------
 xen/arch/x86/cpu/microcode/intel.c |  7 ++-----
 xen/include/xen/xmalloc.h          | 11 +++++++++++
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/cpu/microcode/amd.c b/xen/arch/x86/cpu/microcode/amd.c
index 0998a36b5c..12a3b6b32c 100644
--- a/xen/arch/x86/cpu/microcode/amd.c
+++ b/xen/arch/x86/cpu/microcode/amd.c
@@ -299,11 +299,10 @@ static int get_ucode_from_buffer_amd(
         return -EINVAL;
     }
 
-    mc_amd->mpb = xmalloc_bytes(mpbuf->len);
+    mc_amd->mpb = xmemdup_bytes(mpbuf->data, mpbuf->len);
     if ( !mc_amd->mpb )
         return -ENOMEM;
     mc_amd->mpb_size = mpbuf->len;
-    memcpy(mc_amd->mpb, mpbuf->data, mpbuf->len);
 
     pr_debug("microcode: CPU%d size %zu, block size %u offset %zu equivID %#x 
rev %#x\n",
              smp_processor_id(), bufsize, mpbuf->len, *offset,
@@ -336,14 +335,10 @@ static int install_equiv_cpu_table(
         return -EINVAL;
     }
 
-    mc_amd->equiv_cpu_table = xmalloc_bytes(mpbuf->len);
+    mc_amd->equiv_cpu_table = xmemdup_bytes(mpbuf->data, mpbuf->len);
     if ( !mc_amd->equiv_cpu_table )
-    {
-        printk(KERN_ERR "microcode: Cannot allocate memory for equivalent cpu 
table\n");
         return -ENOMEM;
-    }
 
-    memcpy(mc_amd->equiv_cpu_table, mpbuf->data, mpbuf->len);
     mc_amd->equiv_cpu_table_size = mpbuf->len;
 
     return 0;
diff --git a/xen/arch/x86/cpu/microcode/intel.c 
b/xen/arch/x86/cpu/microcode/intel.c
index 6ac5f98694..f26511da98 100644
--- a/xen/arch/x86/cpu/microcode/intel.c
+++ b/xen/arch/x86/cpu/microcode/intel.c
@@ -339,13 +339,10 @@ static long get_next_ucode_from_buffer(struct 
microcode_intel **mc,
         return -EINVAL;
     }
 
-    *mc = xmalloc_bytes(total_size);
+    *mc = xmemdup_bytes(mc_header, total_size);
     if ( *mc == NULL )
-    {
-        printk(KERN_ERR "microcode: error! Can not allocate memory\n");
         return -ENOMEM;
-    }
-    memcpy(*mc, (const void *)(buf + offset), total_size);
+
     return offset + total_size;
 }
 
diff --git a/xen/include/xen/xmalloc.h b/xen/include/xen/xmalloc.h
index f515ceee2a..16979a117c 100644
--- a/xen/include/xen/xmalloc.h
+++ b/xen/include/xen/xmalloc.h
@@ -51,6 +51,17 @@
 #define xmalloc_bytes(_bytes) _xmalloc(_bytes, SMP_CACHE_BYTES)
 #define xzalloc_bytes(_bytes) _xzalloc(_bytes, SMP_CACHE_BYTES)
 
+/* Allocate untyped storage and copying an existing instance. */
+#define xmemdup_bytes(_src, _nr)                \
+    ({                                          \
+        unsigned long nr_ = (_nr);              \
+        void *dst_ = xmalloc_bytes(nr_);        \
+                                                \
+        if ( dst_ )                             \
+            memcpy(dst_, _src, nr_);            \
+        dst_;                                   \
+    })
+
 /* Free any of the above. */
 extern void xfree(void *);
 
-- 
2.11.0


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